SAN ONOFRE SEISMIC STUDIES MAY SHRINK

Mandated assessments not as crucial after plant closure

The operator of the San Onofre Nuclear Generating Station is likely to scale back a robust slate of earthquake studies as it moves forward with retiring the coastal power plant.

Nuclear plants across the country are reassessing their seismic risks to comply with new federal requirements adopted largely in response to the March 2011 Japan earthquake, tsunami and meltdown at the Fukushima Daiichi facility.

Southern California Edison contracted with at least three universities to help reassess seismic hazards at San Onofre, but those plans have been thrown into limbo by its June 7 announcement that the twin-reactor plant is closing for good. The plant stopped producing power in January 2012 because of the rapid degradation of some steam generators.

Edison said it has spent about 10 percent of the $64 million authorized by state utility regulators for offshore geological surveys, analysis and other work.

“Our goal is to limit spending as a result of the plant shutdown,” Edison spokeswoman Maureen Brown said in an email. “There may be costs going forward that are associated with meeting continuing federal regulatory requirements, and we also may incur some costs as we wind down work associated with state initiatives.”

A spokeswoman for the state utilities commission said the scope of seismic studies at and around the area may need to change.

“Spent (nuclear) fuel will be stored on-site for some time,” Terrie Prosper said. “We still must assure we know the seismic risks to the site.”

The San Onofre seismic project was a potential scientific boon, in particular, to the Scripps Institution of Oceanography, which has been awarded at least $4.8 million to date. Officials at Scripps, which brings in more than $100 million in research funding annually, said the status of the research going forward was unclear.

San Onofre is in the process of transferring remaining nuclear fuel from the Unit 2 reactor to cooling pools, where the material remains for about five years before being moved to long-term dry storage casks of reinforced steel and concrete.

Scott Burnell, a spokesman for the Nuclear Regulatory Commission, said the plant in the near future should no longer need to comply with seismic standards designed to ensure the safety of core reactor cooling systems.

“There is still the question of continuing to comply with our regulations for spent-fuel pool cooling,” he said. “It would be a case of the plan operator saying this order doesn’t apply with us anymore.”

Questions about whether it was reasonable for Edison to proceed with funding seismic research in recent months as it grappled with salvaging faulty steam generators will be left to the California Public Utilities Commission.

The commission is in the early stages of ruling on who will pay for more than $1 billion in costs associated with the outage. San Diego Gas & Electric is a minority owner in San Onofre, so its customers may have some financial liability.

John Geesman, an attorney for the Alliance for Nuclear Responsibility, said it is unclear whether the quake research still has relevance. “You’ve got an evolving seismic risk profile. It’s different from having an operating reactor on the site,” he said. “It’s a $64 million conundrum.”

Edison said it already has paid Scripps and the University of Nevada to reanalyze historic data on offshore geology. San Diego State University has been paid to look for signs of ancient earthquakes in the area.

San Onofre’s two reactors were built in the late 1970s and early ’80s to withstand a peak ground acceleration of 0.67 times the force of gravity, on a scale used for building codes and design risk. Among U.S. nuclear power plants, only Diablo Canyon is built to a more rigorous standard, according to the Nuclear Regulatory Commission.